Pneumatic vehicle tire with optimized recyclability

ABSTRACT

A pneumatic vehicle tire has two beads each having a bead core and a carcass of at least one layer anchored at the bead cores within the beads. The beads further have bead profiling members. A reinforcement structure is located radially outwardly of the carcass, and a tread is positioned radially outwardly of the reinforcement structure. The carcass is made of aramid cord fabric and the bead cores are made of aramid cords. The reinforcement structure is made of synthetic fiber-reinforced rubber or of aramid cords. The bead profiling members are made of rubber reinforced with synthetic fibers.

BACKGROUND OF THE INVENTION

The present invention relates to a built or assembled pneumatic vehicletire, especially tires for trucks and heavy equipment, with a single- ormulti-layer reinforcement carcass which is anchored in the beads bywinding about the bead cores, with bead profiling members in the beads,and with a tire tread as well as a reinforcement structure positionedbetween the carcass and the tire tread. Conventional pneumatic vehicletires for commercial vehicles (trucks and heavy equipment) are providedwith a carcass made of steel cord whereby also a multi-layer belt isprovided that is also comprised of steel cord. Furthermore, the beadcores are also made of steel wires. When bead reinforcement members areprovided, they, in general, are also made of steel cord strips. Thus,steel as a tire building material considerably contributes to the totalweight of the tire.

Recently, recyclability of used tires has become more and moreimportant. In this context, shredding of the tires with high steel cordcontents presents a considerable problem. Furthermore, it is verydifficult to remove the rubber adhering to the steel cord from the steelcords.

It is therefore an object of the present invention to provide apneumatic vehicle tire of the aforementioned kind which allows for anoptimized recyclability.

SUMMARY OF THE INVENTION

The pneumatic vehicle tire according to the present invention isprimarily characterized by:

Two beads each having a bead core;

A carcass of at least one layer anchored at the bead cores within thebeads;

The beads further comprising bead profiling members;

A reinforcement structure located radially outwardly of the carcass;

A tread positioned radially outwardly of the reinforcement structure;

The carcass essentially consisting of aramid cord fabric;

The bead cores essentially consisting of aramid cords;

The reinforcement structure essentially consisting of rubber reinforcedwith synthetic fibers; and

The bead profiling members essentially consisting of rubber reinforcedwith synthetic fibers.

Advantageously, each one of the beads includes a bead reinforcementelement essentially consisting of rubber reinforced with syntheticfibers. Preferably, the rubber reinforced with synthetic fibers of thebead reinforcement elements is identical to the rubber reinforced withsynthetic fibers of the reinforcement structure and the bead profilingmembers.

Expediently, the rubber reinforced with synthetic fibers contains 10% to50% by weight synthetic fibers. Preferably, the synthetic fibers consistof aramid. Advantageously, the synthetic fibers have a length of 0.01 mmto 6 mm and have a diameter of 5 μm to 100 μm.

In another embodiment of the present invention, the pneumatic vehicletire is primarily characterized by:

Two beads each having a bead core;

A carcass of at least one layer anchored at the bead cores within thebeads;

The beads further comprising bead profiling members;

A reinforcement structure located radially outwardly of the carcass;

A tread positioned radially outwardly of the reinforcement belt;

The carcass made of aramid cord fabric;

The bead cores made of aramid fibers;

The reinforcement structure made of aramid cords; and

The bead profiling members made of rubber reinforced with syntheticfibers.

Advantageously, each of the beads includes a bead reinforcement elementmade of rubber reinforced with synthetic fibers.

Preferably, the rubber reinforced with synthetic fibers of the beadreinforcement elements is identical to the rubber reinforced withsynthetic fibers of the bead profiling members.

Preferably, the rubber reinforced with synthetic fibers contains 10% to50% by weight synthetic fibers. Preferably, the synthetic fibers arearamid. Expediently, the synthetic fibers have a length of 0.01 mm to 6mm and have a diameter of 5 μm to 100 μm.

In another embodiment of the present invention, the reinforcementstructure is comprised of a plurality of reinforcement layers withneighboring ones of the reinforcement layers positioned in a crossedreinforcement arrangement.

Preferably, the reinforcement structure is comprised of continuouswindings of aramid cords. Alternatively, the reinforcement structure iscomprised of continuous windings of material strips comprised of aplurality of aramid cords.

According to the present invention, the carcass is comprised of a fabricmade of aramid cords, the bead cores are made of aramid fibers and thereinforcement structure as well as the bead profiling members are madeof rubber reinforced with synthetic fibers. According to anothersolution the reinforcement structure is comprised of a plurality oflayers of aramid cords instead of the rubber reinforced with syntheticfibers.

By suggesting a pneumatic vehicle tire that is free of steel, theseparation of rubber and steel cord during the recycling process of theused vehicle tire is obsolete. Also, the known problems encountered whenshredding the tire no longer exist. It is thus possible to perform apyrolytic or hydrolytic decomposition of the entire tire material.

A further technical advantage of the present invention is that theweight of a truck tire is reduced by approximately 25% resulting in areduced rolling resistance. Due to the considerable reduction of thetire weight, it is thus possible to allow for a greater pay load. Thereduced rolling resistance also results in fuel savings. Furthermore, itis advantageous that by using rubber reinforced with synthetic fibers atthe different locations within the tire, especially within thereinforcement structure, a stiffness discontinuity or a stiffness leapbetween these parts and the neighboring rubber is reduced so that therubber components in the named areas are subjected to a considerablyreduced load.

The invention with all its advantages is especially useful for pneumaticvehicle tires for trucks (commercial vehicles), however, in general, thetire of the present invention is also suitable for automobiles.

According to a further embodiment of the invention the beadreinforcement elements of the tire are also made of rubber reinforcedwith synthetic fibers. Within the different tire components the rubberreinforced with synthetic fibers may have a synthetic fiber content of10% to 50% by weight, preferably of approximately 25% by weight.

The plastic material to be used for the synthetic fibers is preferablyaramid; however, if desired, it is, of course, also possible to useother plastic materials to produce synthetic fibers. The use of aramidis advantageous because the entire pneumatic vehicle tire is thencomprised of only one single plastic material which during recyclingresults in considerable simplifications of the process.

The synthetic fibers to be employed may have a length of 0.01 to 6 mm,whereby preferably fibers of 0.1 to 2 mm in length are used. The fibersmay be present in different lengths of the suggested range, but may alsobe provided with a certain constant length. The synthetic (plastic)fibers may have a diameter of 5 to 100 μm. Especially for the rubber tobe used as the reinforcement structure, it may be advantageous that thesynthetic fibers are introduced into the rubber plate for building thetire in a certain orientation.

BRIEF DESCRIPTION OF THE DRAWINGS

The object and advantages of the present invention will appear moreclearly from the following specification in conjunction with theaccompanying drawings, in which:

FIG. 1 shows a pneumatic vehicle tire for commercial vehicles in aradial cross-section; and

FIG. 2 shows the pneumatic vehicle tire of FIG. 1 with a belt made ofaramid cord fabric.

DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention will now be described in detail with the aid ofseveral specific embodiments utilizing FIGS. 1 and 2.

The pneumatic vehicle tire of FIG. 1 has a carcass 1 which, for example,can be a radial carcass and may be comprised of aramid cord fabric. Thecarcass 1 is anchored in the area of the beads 2 by winding about thepull-resistant bead cores 3. Radially outwardly of the bead cores 3 oneach side of the tire a bead profiling member 4 is provided. Axiallyoutwardly of the bead core 3 and the bead profiling member 4 a beadreinforcement element 5 is arranged.

Between the carcass 1 and the tire tread 6 a reinforcement structure 7is arranged. The reinforcement structure 7 is comprised of rubberreinforced with synthetic fibers in which, for example, aramid is usedas the synthetic fiber. During building of the tire the reinforcementstructure 7 may be assembled by placing one or a plurality of rubberplates made of rubber reinforced with synthetic fibers onto the carcass.It is possible to use as many as five rubber plates. The syntheticfibers within the individual rubber plates may be arranged in certainorientations.

The bead profiling member 4 is comprised of rubber reinforced withsynthetic fibers whereby the plastic material for the synthetic fibersis again aramid. The bead reinforcement elements 5 may be comprised ofthe same material. By using synthetic fibers within the beadreinforcement elements 5 chafing and friction within the area of the rimflanges are reduced or prevented. The bead cores 3 which may be of ahexagonal or round or square cross-section may also be comprised ofaramid cords as the carcass 1. The aramid cords are wound in thecircumferential direction to form a core package.

In the case of tires for automobiles it is possible to build a tirewithout the bead reinforcement elements 5 and to design the bead cores 3of a smaller size, for example, with a round cross-section. Furthermore,it is sufficient for automobile tires to provide a reduced number ofcarcass layers as well as a reinforcement structure 7 that is thinner.

The tire of FIG. 2 is essentially identical to the tire of FIG. 1 withthe exception of the reinforcement structure 7. Instead of thereinforcement structure 7 made of rubber reinforced with syntheticfibers, the tire according to FIG. 2 is provided with a three-layer belt8 whereby each layer has reinforcements in the form of aramid fibers oraramid cords. Preferably, the aramid cords extend within one layerparallel to one another, but at a slant to the circumferential directionof the tire whereby they may have an angle of 15° to 70° to thecircumferential tire direction. The cord fabric of neighboring layers isarranged in a crossed reinforcement arrangement as is conventional. Foran improved adhesion of the aramid cord or aramid fibers within the tirethey are embedded in a rubber coating. The aramid fibers or aramid cordshave a diameter of 0.7 to 2 mm and have a fiber density of 40 to 80fibers per 10 cm.

If so desired, the belt 8, of course, may be comprised of only twolayers or may have four or five layers. It should be noted that the belt8 may also be produced by winding aramid cord or preferably a materialstrip made of a plurality of aramid cords onto the carcass. The materialstrips are then wound in a plurality of windings that are placeddirectly adjacent to one another or in an overlapping arrangement.

The present invention is, of course, in no way restricted to thespecific disclosure of the specification and drawings, but alsoencompasses any modifications within the scope of the appended claims.

What we claim is:
 1. A pneumatic vehicle tire comprising:two beads eachhaving a bead core; a carcass of at least one layer anchored at saidbead cores within said beads; said beads further comprising beadprofiling members; a reinforcement structure located radially outwardlyof said carcass; a tread positioned radially outwardly of saidreinforcement structure; said carcass consisting essentially of aramidcord fabric; said bead cores consisting essentially of aramid cords;said reinforcement structure consisting essentially of rubber reinforcedwith synthetic fibers; and said bead profiling members consistingessentially of rubber reinforced with synthetic fibers.
 2. A tireaccording to claim 1, wherein each one of said beads includes a beadreinforcement element consisting essentially of rubber reinforced withsynthetic fibers.
 3. A tire according to claim 2, wherein said rubberreinforced with synthetic fibers of said bead reinforcement elements isidentical to said rubber reinforced with synthetic fibers of saidreinforcement structure and said bead profiling members.
 4. A tireaccording to claim 1, wherein said rubber reinforced with syntheticfibers contains 10% to 50% by weight synthetic fibers.
 5. A tireaccording to claim 3, wherein said synthetic fibers are aramid.
 6. Atire according to claim 3, wherein said synthetic fibers have a lengthof 0.01 mm to 6 mm.
 7. A tire according to claim 3, wherein saidsynthetic fibers have a diameter of 5 μm to 100 μm.